Tretinoin, explained
The strongest, best-researched retinoid for ageing skin, and prescription-only in the UK. Here’s what it does, how to get it safely, and how it compares with the retinol and retinal in K-beauty.
What it is
Tretinoin (also called retinoic acid or Retin-A) is the active form of vitamin A. Retinol and retinal, the retinoids you can buy in shops, have to be converted by your skin into retinoic acid before they work. Tretinoin skips those steps, which is why it’s stronger, and also why it’s more likely to irritate.
The vitamin A family, weakest to strongest: retinyl esters → retinol → retinal → tretinoin (retinoic acid).
What the research shows
Tretinoin has been studied for decades and is the best-researched topical treatment for sun-damaged, ageing skin. Trials show it improves fine wrinkles, roughness and blotchy pigmentation, usually over 3 to 6 months or more.
Darlenski and colleagues, British Journal of Dermatology, 2010 [1]
It’s also a long-standing treatment for acne, which some women find returns around perimenopause.
How to get it in the UK
Tretinoin is a prescription-only medicine in the UK, so you can’t buy it at Boots, Superdrug or any beauty shop [2]. The NHS rarely prescribes it for ageing skin, so most people get it privately:
- A dermatologist or private GP, in person.
- Online prescription services such as Dermatica, Skin+Me and Renew+Me (Skin+Me’s service for midlife women), where a prescriber reviews an online consultation and photos before sending a personalised cream [2][3].
Avoid websites selling tretinoin without a prescription. It isn’t legal or safe, and you can’t be sure what you’re getting [2]. We’re not affiliated with any of these services.
You won’t find tretinoin in K-beauty products. Korean skincare uses retinol and retinal instead, which you can buy freely.
Starting tretinoin after 40
- Start low and slow. Prescribers usually begin with a low strength a few nights a week and build up.
- Expect an adjustment phase. Dryness, flaking and redness are common in the first weeks, and some people get breakouts for a while.
- Keep the rest of your routine gentle. A mild cleanser, a barrier cream with ceramides, and no exfoliating acids on the same night. Our pairing guide shows what clashes.
- Wear sunscreen every day. Tretinoin makes skin more sensitive to the sun.
- Not during pregnancy or breastfeeding, or if you’re trying to conceive. Tell your prescriber about any medicines or skin conditions, including rosacea or eczema.
Tretinoin vs retinol and retinal
| Retinol | Retinal | Tretinoin | |
|---|---|---|---|
| Strength | Gentlest | Middle | Strongest |
| Evidence | Good | Good, growing | Strongest |
| Irritation | Lowest | Low to medium | Highest |
| How to buy | Any shop | Any shop | Prescription only |
If you’re new to retinoids or have sensitive skin, starting with a shop-bought retinol or retinal is a sensible first step. See our UK vs Korea retinoid comparison for budget options.
Sources
- Darlenski R, Surber C, Fluhr JW. Topical retinoids in the management of photodamaged skin: from theory to evidence-based practical approach. Br J Dermatol. 2010.
- Where to get tretinoin online in the UK. City Skin Clinic.
- How to get tretinoin. Marie Claire UK.
This page is general information, not medical advice. Last updated 31 October 2026.